P48 Major Surface Antigen of Mycoplasma agalactiae Is Homologous to a malp Product of Mycoplasma fermentans and Belongs to a Selected Family of Bacterial Lipoproteins

Abstract

A major surface antigenic lipoprotein of Mycoplasma agalactiae, promptly recognized by the host's immune system, was characterized. The mature product, P48, showed significant similarity and shared conserved amino acid motifs with lipoproteins or predicted lipoproteins from Mycoplasma fermentans, Mycoplasma hyorhinis, relapsing fever Borrelia spp.,Bacillus subtilis, and Treponema pallidum.

Sequence, cloning, expression and characterisation of the 81-kDa surface membrane protein (P80) of Mycoplasma agalactiae

“…A posttranslational cleavage site for signal peptidase II, deduced from the amino-terminal sequence, was located between residues Ser-23 and Ala-25 (i.e., AVSsAKC) instead of Ala-25 and Lys-26 (i.e., VSAsKC) used by other Grampositive and Gram-negative bacteria [20,22]. This is in agreement with the consensus sequence found in other M. agalactiae lipoproteins: P48 and Vpma [10,11]. Both lipoproteins are subjected to a cleavage that occurs two amino acids before the ¢rst Cys residue : P48 (VAsASC) and Vpma (AsAKC).…”

Molecular characterization of theMycoplasma bovis p68gene, encoding a basic membrane protein with homology to P48 ofMycoplasma agalactiae

“…For example, the malp of M. fermentans was identified upstream of four genes, p63-p58-p35-p78, which comprise an ABC transporter operon (Calcutt et al, 1999). The p48 of M. agalactiae (Rosati et al, 1999) and p48 in M. bovis (Robino et al, 2005) are adjacent to putative ABC transporters. The relation and proximity to ABC transporters support the idea of a common, as yet unknown, function for BMPs possessing the SLA motifs.…”

“…Until now, only one malp-related gene has been described in mycoplasmal genomes (Calcutt et al, 1999;Rosati et al, 1999;Markham et al, 2003;Robino et al, 2005). The identification of the p68 gene as a malp-related gene in M. bovis represents the first example of two copies of malprelated genes in the mycoplasma.…”

“…Interestingly, the location of the SLA-1 and SLA-2 motifs within the P48 coding region of M. bovis was similarly positioned as in the other lipoproteins, with SLA-1 positioned at 78-84 residues downstream of the initiation codon and the SLA-2 motif of P48 localized 251 residues downstream of the SLA-1 motif. The SLA-1 and SLA-2 motifs of the P48-like protein (DESFNQS and FIIGVDADQ) exhibited 100% identity to their counterparts from the P48 protein of M. agalactiae (Rosati et al, 1999). In the P68 protein, however, the SLA-1 and the SLA-2 motifs were found 221 and 461 residues downstream of the P68 initiation codon, respectively.…”

“…One of the significant features of BMPs is the presence of SLA motifs (Fig. 1a), which have been identified in the M. fermentans MALP-404 (Calcutt et al, 1999) and in the MALP homologs of M. gallisepticum (Markham et al, 2003), M. agalactiae (Rosati et al, 1999), and P48 of M. bovis (Robino et al, 2005).…”